package cn.net.springboot.netty.http_demo;

import io.netty.bootstrap.Bootstrap;
import io.netty.channel.ChannelFuture;
import io.netty.channel.ChannelHandlerContext;
import io.netty.channel.ChannelInitializer;
import io.netty.channel.ChannelPipeline;
import io.netty.channel.EventLoopGroup;
import io.netty.channel.SimpleChannelInboundHandler;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.channel.socket.nio.NioSocketChannel;
import io.netty.handler.codec.LengthFieldBasedFrameDecoder;
import io.netty.handler.codec.LengthFieldPrepender;
import io.netty.handler.codec.string.StringDecoder;
import io.netty.handler.codec.string.StringEncoder;
import io.netty.util.CharsetUtil;
import java.time.LocalDateTime;

public class MyClient {
    public static void main(String[] args) throws Exception {
        EventLoopGroup eventLoopGroup = new NioEventLoopGroup();
        try {
            Bootstrap bootstrap = new Bootstrap();
            bootstrap.group(eventLoopGroup)
                    .channel(NioSocketChannel.class)
                    .handler(new MyClientInitializer());
            ChannelFuture channelFuture = bootstrap.connect("127.0.0.1", 8899).sync();
            channelFuture.channel().closeFuture().sync();
        } finally {
            eventLoopGroup.shutdownGracefully();
        }
    }

    static class MyClientInitializer extends ChannelInitializer<NioSocketChannel> {
        @Override
        protected void initChannel(NioSocketChannel ch) throws Exception {
            ChannelPipeline pipeline = ch.pipeline();
            pipeline.addLast(new LengthFieldBasedFrameDecoder(Integer.MAX_VALUE, 0, 4, 0, 4));
            pipeline.addLast(new LengthFieldPrepender(4));
            pipeline.addLast(new StringDecoder(CharsetUtil.UTF_8));
            pipeline.addLast(new StringEncoder(CharsetUtil.UTF_8));
            pipeline.addLast(new MyClientHandler());
        }
    }

    static class MyClientHandler extends SimpleChannelInboundHandler<String> {
        @Override
        protected void channelRead0(ChannelHandlerContext ctx, String msg) throws Exception {
            System.out.println(ctx.channel().remoteAddress());
            System.out.println("client output" + msg);
            ctx.writeAndFlush("from client:" + LocalDateTime.now());
        }

        @Override
        public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) throws Exception {
            cause.printStackTrace();
            ctx.close();
        }

        @Override
        public void channelActive(ChannelHandlerContext ctx) throws Exception {
            ctx.writeAndFlush("来自客户端的问候！");
        }
    }

}